A. Field of the Invention
The present invention is related with the art of manufacturing glassware articles and more particularly with an apparatus for cutting off molten glass gobs from a continuous flow of molten glass.
B. Description of the Previous Art
It is well known to form glassware articles from a continuous flow of molten glass from a glass feeder, which is sheared into individual molten glass gobs which are employed to form glassware articles therefrom.
Said molten glass gobs are formed by a shearing apparatus placed under the glass feeder and which usually consist of a pair of shear blades operated by a drive mechanism.
The most common shearing apparatus includes a pair of arms each having first and second ends. Shear blades are mounted on said first ends in opposed relationship and said second ends are coupled to a driving mechanism which provide a reciprocating movement to both arms so as to close and open the first ends carrying said blades to shear the continuous flow of molten glass into a plurality of individual molten glass gobs, as disclosed in the U.S. Pat. Nos. 2,401,994 of Wever; 2,812,619 of F. J. Wythe. 3,758,286 of Heyne and 3,850,607.
Another type of glass gob shearing apparatus is disclosed in the U.S. Pat. No. 3,786,707 of Becker et al. That apparatus comprises a pair of shear blades each respectively supported on a shaft mounted between a pair of rotatable disks driven by a motor. Rotation of the disks is allowed while rotation of the shafts is prevented. Consequently, on each rotation of the disks the shear blades coincide one against the other to cut off a glass gob from the continuous molten glass flow.
Still another type of glass gob shearing apparatus comprise a pair of shear bladed, each slide mounted on a pair of shafts or supporting elements and drive means are provided to impart a linear reciprocal movement to said blades in order to cut off a glass gob in each reciprocating run, as disclosed by the U.S. Pat. Nos. 3,996,037; 4,214,497 and 4,246,819 of Dahms.
All of these shearing apparatuses have the problem that, because of the "scissor type" arrangement of its shear blades, they are susceptible of misalignment and improper meeting causing deformation in the glass gobs and "cutting marks" such as thin long "scratches" in the surface of the gobs and "bites" in its ends, which result in defective glassware articles.
Furthermore, as these defects are not detectable until the finished ware is inspected, these deformations and "cutting marks" can result in a significant quantity of defective articles before the problem be detected and corrected and therefore these shearing apparatus require of continuous supervision and additional sophisticated control and correcting apparatuses.
The shearing apparatus of the present invention overcome all of above disclosed problems and drawbacks by providing a single shear blade driven in such a way that its cutting velocity profile is controlled in order to provide its faster velocity on reaching near to the molten glass flow and instantaneously impact and cut off said glass flow forming a glass gob of desired length and weight.